"Every week there's something new going on. There's a new move," Urban, 46, explained on the red carpet at the Grammys – where he was nominated for best country duo/group performance for "Highway Don't Care" with Taylor Swift and Tim McGraw. "There's a new word in their vocabulary. Right now for Sunday, everything's 'that's weird.' "

Sunday Rose and younger sister, 3-year-old Faith Margaret – who are "growing rapidly" according to Urban – weren't onhand to witness their father's spot on Sunday evening, where he performed "Cop Car" with Gary Clarke Jr.